Crystal Lab › Prototype structures › Orthorhombic
Spertiniite [Cu(OH)₂]
Orthorhombic · space group Cmc21 (No. 36) · Pearson oC20 · mineral: spertiniite
Symmetry elements and Wyckoff positions (interactive)
Spertiniite [Cu(OH)₂] in Cmc21
SettingUnit cell
- Lattice constants
- a = 2.947 Å, b = 10.593 Å, c = 5.256 Å; α = 90.00°, β = 90.00°, γ = 90.00°
- Cell volume
- 164.1 ų
- Atoms in the conventional cell
- 20 (Cu 4, H 8, O 8)
- Formula units Z
- 4
- Pearson symbol
- oC20 — orthorhombic, base-centred lattice, 20 atoms per conventional cell
- Symmetry operations
- 8 per cell
Crystallographic sites
| Site | Element | Wyckoff | Multiplicity | x | y | z |
|---|---|---|---|---|---|---|
| Cu1 | Cu | 4a | 4 | 0.0000 | 0.1820 | 0.2500 |
| H2 | H | 4a | 4 | 0.0000 | 0.5058 | 0.4118 |
| H3 | H | 4a | 4 | 0.0000 | 0.9001 | 0.1914 |
| O4 | O | 4a | 4 | 0.0000 | 0.5583 | 0.2534 |
| O5 | O | 4a | 4 | 0.0000 | 0.7994 | 0.1967 |
The multiplicity and the Wyckoff letter say how many copies of the site the group makes in one cell and on which kind of symmetry element the site sits; the 20 atoms drawn above are these sites multiplied by all 8 operations. Press Wyckoff under Colour to see the sites, and tick a symmetry element on the left to see which atoms lie on it.
How to read the label
AB2C2_oC20_36_a_2a_2a-001: the stoichiometry comes first (A, B, C… are the elements in alphabetical order of their site labels), then the Pearson symbol oC20, then the space-group number 36, then the Wyckoff letters occupied by each element in turn (Cu: 4a; H: 4a; H: 4a; O: 4a; O: 4a). Two structures with the same label are the same arrangement with different cell parameters or coordinates.
Note: Spertiniite.
Source
Coordinates and cell from the AFLOW Encyclopedia of Crystallographic Prototypes, entry AB2C2_oC20_36_a_2a_2a-001 (M. J. Mehl et al., Comput. Mater. Sci. 136, S1 (2017); D. Hicks et al., ibid. 161, S1 (2019) and 199, 110450 (2021); S. Eckert et al., ibid. 240, 112988 (2024)). Symmetry elements, Wyckoff assignment and the diagram are computed on this page from the group operations.
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